A teenager's first hit of synthetic cannabis was so frightening she was turned off for life.

‘‘I tried synthetic weed because it was offered around my friends. I had one hit and instantly my heart started beating really fast,’’ she said.

‘‘Then it just got faster and faster and I couldn’t feel my arms or legs.

‘‘My friends told me my skin went pale, I went yellow in the eyes and I was sweating really bad.

‘‘That went on for about an hour and it was the scariest time of my life. Nothing made me feel better.

‘‘Then I started seeing things, all kinds of strange visions, I felt like I was in a scary movie and I couldn’t get out.

‘‘I finally came good but ever since that day, I’ve had trouble with my memory and sometimes I feel like I miss a few seconds, almost like I blank out.

‘‘I get crazy headaches that I’ve never had before and shooting pain through my body. I’ll never touch it again.’’

The teenager urged people to stop referring to the substances as ‘‘synthetic cannabis or synthetic weed or anything else that makes it sound like these chemicals are anything like cannabis. They’re not.’’

‘‘This stuff is poison,’’ she said.

Drugs big risk to teens

Police are playing catch-up with drug manufacturers who are mixing untested chemical compounds into products that end up in the hands of Illawarra teenagers, an expert has warned.

"They started out flooding the market several years ago, using known synthesised cannabinoid compounds that had been used in animal and brain research studies, not in humans," explained Associate Professor Nadia Solowij, from the University of Wollongong's School of Psychology.

"Those compounds were quite similar to THC, the primary psychoactive ingredient in cannabis, but often stronger, which caused some adverse effects when humans consumed them."

Prof Solowij said the manufacturers would spray those liquid compounds onto other general green plant matter and there was no law against those compounds being sold in those specific kinds of preparations, so they were considered a "legal high".

"When the authorities cottoned on to what was happening, they banned any preparation of those compounds," she said.

"The manufacturers were well prepared for such a bust, and so the very next day released their new range of products, almost exactly the same but the compounds modified just slightly to get around the law.

"And it's been a case of catch-up ever since ... laws being changed to counter these kinds of changes and each time new products coming on the market to get around the laws ... and it has spiralled, until what is available today is far removed from resembling cannabis at all."

Prof Solowij said often the chemical compounds were not even synthetic cannabinoids any more "but something quite different".

"People have no idea what they are consuming and there is no wonder that there have been some severe reactions."